The expensive "Cassis bourgeous" and, to a greater extent, buchu leaf oil, the essential oil of barosma betulina (Bartl. & Wendl.) have been in use in the perfume and flavoring industry for many years. This oil is available in varying qualities and amounts, but always at a relatively high price. The interesting fragrance complex of buchu leaf oil, with fresh sweet and green-herby notes and a very typical "blackcurrent" character, has prompted various study groups to analyse the oil (E. Sundt, B. Wilhalm, R. Chappaz and G. Ohloff, Helv. Chim. Acta 54, 1801 (1971); D. Lamparsky and P. Schudel, Parfums, Mosm/e/ t. Savons Fr. 2, 465 (1972)). In particular, these revealed that menthon-thiol is the carrier of the "blackcurrent" note. Menthon-thiol is shown in patents (D. Lamparsky and P. Schudel, DT-OS No. 2 043 341, E. Sundt and G. Ohloff, CH-PS No. 543 584).
In the field of perfumery, only a limited number of oximes of aliphatic aldehydes or ketones with 7-10 carbon atoms are known (R. T. Dahill, U.S. Pat. No. 3,637,533, Jan. 25, 1972; i.e. DT-PS No. 1,692,002). These aldehydes and ketones (e.g. 2-methyl-2-hepten-6-one, citronellal) are common fragrance chemicals with fruity or citrus notes. The scent of the associated oximes differs from this and has been characterised as "green-leafy", "green-earthy" "flowery".